Yellow-footed Gull (Larus livens) (1)- Reported Feb 20, 2017 16:05 by Curtis Marantz- Rio Hondo Coastal Spreading Grounds, Los Angeles, California- Map: http://maps.google.com/?ie=UTF8&t=p&z=13&q=33.9958925,-118.0994654&ll=33.9958925,-118.0994654- Checklist: http://ebird.org/ebird/view/checklist/S34603085- Comments: "This was a large, heavy-bodied gull that differed little from the adult Western Gulls in its size, structure, and plumage patterns. Although the bill stood out as larger, and even more obviously, stouter than those of at least most of the Western Gulls, I am not sure it would have been separable from the largest-billed individuals in the flock. The culmen was straight until curving downward near the tip, and the angle at the gonys appeared to be relatively weak because the bill was stout throughout its length. This bird's bill may have been a little longer than those of the Western Gulls, but my impression was that the greatest difference between the two species was and how stout this bird's bill appeared. This bird seemed to have a proportionately larger head than did those of the other birds, but I suspect the sloping forehead, gently rounded crown, and the angular junction of the crown with the forehead and the more sharply rounded junction with the crown and the nape were indicative of this bird being a male. Apart from the subtle, structural differences in the bill and head, this bird appeared essentially like a large Western Gull. The neck was short and stout, the body was plump, the wings appeared to be relatively short, and the tail was short and squared-tipped. I saw the tips of four primaries extending beyond the tertials in a tapered wingtip that extended just beyond the tip of the tail. As I recall, the primary projection was only slightly longer than the exposed tertials. The tail was less than one-half the length of the body without the head and neck. I saw the legs and feet only briefly, yet I noted that the legs were relatively short and that the feet were fully webbed.This bird's plumage patterns were essentially identical to those of the Western Gulls. The head, neck, breast, sides, flanks, and what I could see of the belly and undertail coverts were snow-white and completely unmarked, with no suggestion whatsoever of streaking on the face, crown, or back or sides of the neck. I also noted that the rump and tail were entirely white and unmarked. Contrasting with the white of the head, neck, and underparts, the back, scapulars, wing coverts, and tertials were a slate-gray in color. The only pattern that I noted on these regions resulted from broad, white tips to the rear scapulars, which produced a conspicuous scapular-crescent, and equally broad tips of white to the tertials that produced a tertial-crescent that was at least as broad as those of the Western Gulls at the extreme end of the range for this character. The exposed primary tips were black, but the four primaries evident on the upperside of the closed wing each had a small, white spot at the tip. When the bird spread the wing slightly, I further noted that the next primary inward had a similar tip that was presumably covered by the tertials in the fully closed wing. Further evident on the far wing as seen from below was a relatively small, white mirror near the tip of the longest primary visible on the underside of the wing; however, I saw little or no additional marking on the underside of the wing. My views of the spread wing were brief, but what I could see appeared to represent white tips to the secondaries that produced a band along the trailing edge of the wing, and mostly white underwings that contrasted with the dusky undersides of at least the primaries.The bill was a deep-yellow in color with a rounded spot of red near the tip of the lower mandible. Given our distance from this bird, it was difficult to discern the color of the eyes, but they did not appear quite as dark as those of at least some of the Western Gulls, and it was relatively certain that I saw a yellow orbital-ring. It was only when this bird raised up as it was bathing, and once when it almost rolled over onto its back, that it revealed that both the legs and webbed feet were a chrome-yellow in color."

Yellow-footed Gull (Larus livens) (1) CONFIRMED- Reported Feb 20, 2017 12:56 by Kimball Garrett- Rio Hondo Spreading Grounds, Los Angeles, California- Map: http://maps.google.com/?ie=UTF8&t=p&z=13&q=33.9954388,-118.0951416&ll=33.9954388,-118.0951416- Checklist: http://ebird.org/ebird/view/checklist/S34598456- Comments: "Adult first located on the west bank by Matt Grube and well-studied by all of us. Virtually identical to nearby adult Western Gulls in mantle color and size (but certainly at the large end of male Westerns), but with deep yellow legs and feet. This yellow color extended to the webs on the toes, and there was no hint of pink on the webbing or around the tarsal joint. The legs appeared thicker than the legs of the largest Western Gulls. Bill color similar to Westerns, though the red spot on the gonys looked a bit brighter and larger; however, the bill was on the long side and noticeably thicker than the bills of any Westerns (enough so that we could pick out the swimming bird on the water even when the legs were not visible). The bird stood and flushed from the west dike, circled, and landed on the water, and we were able to follow it on the water for a long time until it took flight again and landed atop the west bank."